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18cb6368 RC |
1 | /* |
2 | * An I2C driver for the NXP PCF2127 RTC | |
3 | * Copyright 2013 Til-Technologies | |
4 | * | |
5 | * Author: Renaud Cerrato <r.cerrato@til-technologies.fr> | |
6 | * | |
7 | * based on the other drivers in this same directory. | |
8 | * | |
9 | * http://www.nxp.com/documents/data_sheet/PCF2127AT.pdf | |
10 | * | |
11 | * This program is free software; you can redistribute it and/or modify | |
12 | * it under the terms of the GNU General Public License version 2 as | |
13 | * published by the Free Software Foundation. | |
14 | */ | |
15 | ||
16 | #include <linux/i2c.h> | |
17 | #include <linux/bcd.h> | |
18 | #include <linux/rtc.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/of.h> | |
22 | ||
23 | #define DRV_VERSION "0.0.1" | |
24 | ||
25 | #define PCF2127_REG_CTRL1 (0x00) /* Control Register 1 */ | |
26 | #define PCF2127_REG_CTRL2 (0x01) /* Control Register 2 */ | |
27 | #define PCF2127_REG_CTRL3 (0x02) /* Control Register 3 */ | |
28 | #define PCF2127_REG_SC (0x03) /* datetime */ | |
29 | #define PCF2127_REG_MN (0x04) | |
30 | #define PCF2127_REG_HR (0x05) | |
31 | #define PCF2127_REG_DM (0x06) | |
32 | #define PCF2127_REG_DW (0x07) | |
33 | #define PCF2127_REG_MO (0x08) | |
34 | #define PCF2127_REG_YR (0x09) | |
35 | ||
36 | static struct i2c_driver pcf2127_driver; | |
37 | ||
38 | struct pcf2127 { | |
39 | struct rtc_device *rtc; | |
40 | int voltage_low; /* indicates if a low_voltage was detected */ | |
41 | }; | |
42 | ||
43 | /* | |
44 | * In the routines that deal directly with the pcf2127 hardware, we use | |
45 | * rtc_time -- month 0-11, hour 0-23, yr = calendar year-epoch. | |
46 | */ | |
47 | static int pcf2127_get_datetime(struct i2c_client *client, struct rtc_time *tm) | |
48 | { | |
49 | struct pcf2127 *pcf2127 = i2c_get_clientdata(client); | |
50 | unsigned char buf[10] = { PCF2127_REG_CTRL1 }; | |
51 | ||
52 | /* read registers */ | |
53 | if (i2c_master_send(client, buf, 1) != 1 || | |
54 | i2c_master_recv(client, buf, sizeof(buf)) != sizeof(buf)) { | |
55 | dev_err(&client->dev, "%s: read error\n", __func__); | |
56 | return -EIO; | |
57 | } | |
58 | ||
59 | if (buf[PCF2127_REG_CTRL3] & 0x04) { | |
60 | pcf2127->voltage_low = 1; | |
61 | dev_info(&client->dev, | |
62 | "low voltage detected, date/time is not reliable.\n"); | |
63 | } | |
64 | ||
65 | dev_dbg(&client->dev, | |
66 | "%s: raw data is cr1=%02x, cr2=%02x, cr3=%02x, " | |
67 | "sec=%02x, min=%02x, hr=%02x, " | |
68 | "mday=%02x, wday=%02x, mon=%02x, year=%02x\n", | |
69 | __func__, | |
70 | buf[0], buf[1], buf[2], | |
71 | buf[3], buf[4], buf[5], | |
72 | buf[6], buf[7], buf[8], buf[9]); | |
73 | ||
74 | ||
75 | tm->tm_sec = bcd2bin(buf[PCF2127_REG_SC] & 0x7F); | |
76 | tm->tm_min = bcd2bin(buf[PCF2127_REG_MN] & 0x7F); | |
77 | tm->tm_hour = bcd2bin(buf[PCF2127_REG_HR] & 0x3F); /* rtc hr 0-23 */ | |
78 | tm->tm_mday = bcd2bin(buf[PCF2127_REG_DM] & 0x3F); | |
79 | tm->tm_wday = buf[PCF2127_REG_DW] & 0x07; | |
80 | tm->tm_mon = bcd2bin(buf[PCF2127_REG_MO] & 0x1F) - 1; /* rtc mn 1-12 */ | |
81 | tm->tm_year = bcd2bin(buf[PCF2127_REG_YR]); | |
82 | if (tm->tm_year < 70) | |
83 | tm->tm_year += 100; /* assume we are in 1970...2069 */ | |
84 | ||
85 | dev_dbg(&client->dev, "%s: tm is secs=%d, mins=%d, hours=%d, " | |
86 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
87 | __func__, | |
88 | tm->tm_sec, tm->tm_min, tm->tm_hour, | |
89 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); | |
90 | ||
91 | /* the clock can give out invalid datetime, but we cannot return | |
92 | * -EINVAL otherwise hwclock will refuse to set the time on bootup. | |
93 | */ | |
94 | if (rtc_valid_tm(tm) < 0) | |
95 | dev_err(&client->dev, "retrieved date/time is not valid.\n"); | |
96 | ||
97 | return 0; | |
98 | } | |
99 | ||
100 | static int pcf2127_set_datetime(struct i2c_client *client, struct rtc_time *tm) | |
101 | { | |
102 | unsigned char buf[8]; | |
103 | int i = 0, err; | |
104 | ||
105 | dev_dbg(&client->dev, "%s: secs=%d, mins=%d, hours=%d, " | |
106 | "mday=%d, mon=%d, year=%d, wday=%d\n", | |
107 | __func__, | |
108 | tm->tm_sec, tm->tm_min, tm->tm_hour, | |
109 | tm->tm_mday, tm->tm_mon, tm->tm_year, tm->tm_wday); | |
110 | ||
111 | /* start register address */ | |
112 | buf[i++] = PCF2127_REG_SC; | |
113 | ||
114 | /* hours, minutes and seconds */ | |
115 | buf[i++] = bin2bcd(tm->tm_sec); | |
116 | buf[i++] = bin2bcd(tm->tm_min); | |
117 | buf[i++] = bin2bcd(tm->tm_hour); | |
118 | buf[i++] = bin2bcd(tm->tm_mday); | |
119 | buf[i++] = tm->tm_wday & 0x07; | |
120 | ||
121 | /* month, 1 - 12 */ | |
122 | buf[i++] = bin2bcd(tm->tm_mon + 1); | |
123 | ||
124 | /* year */ | |
125 | buf[i++] = bin2bcd(tm->tm_year % 100); | |
126 | ||
127 | /* write register's data */ | |
128 | err = i2c_master_send(client, buf, i); | |
129 | if (err != i) { | |
130 | dev_err(&client->dev, | |
131 | "%s: err=%d", __func__, err); | |
132 | return -EIO; | |
133 | } | |
134 | ||
135 | return 0; | |
136 | } | |
137 | ||
138 | #ifdef CONFIG_RTC_INTF_DEV | |
139 | static int pcf2127_rtc_ioctl(struct device *dev, | |
140 | unsigned int cmd, unsigned long arg) | |
141 | { | |
142 | struct pcf2127 *pcf2127 = i2c_get_clientdata(to_i2c_client(dev)); | |
143 | ||
144 | switch (cmd) { | |
145 | case RTC_VL_READ: | |
146 | if (pcf2127->voltage_low) | |
147 | dev_info(dev, "low voltage detected, date/time is not reliable.\n"); | |
148 | ||
149 | if (copy_to_user((void __user *)arg, &pcf2127->voltage_low, | |
150 | sizeof(int))) | |
151 | return -EFAULT; | |
152 | return 0; | |
153 | default: | |
154 | return -ENOIOCTLCMD; | |
155 | } | |
156 | } | |
157 | #else | |
158 | #define pcf2127_rtc_ioctl NULL | |
159 | #endif | |
160 | ||
161 | static int pcf2127_rtc_read_time(struct device *dev, struct rtc_time *tm) | |
162 | { | |
163 | return pcf2127_get_datetime(to_i2c_client(dev), tm); | |
164 | } | |
165 | ||
166 | static int pcf2127_rtc_set_time(struct device *dev, struct rtc_time *tm) | |
167 | { | |
168 | return pcf2127_set_datetime(to_i2c_client(dev), tm); | |
169 | } | |
170 | ||
171 | static const struct rtc_class_ops pcf2127_rtc_ops = { | |
172 | .ioctl = pcf2127_rtc_ioctl, | |
173 | .read_time = pcf2127_rtc_read_time, | |
174 | .set_time = pcf2127_rtc_set_time, | |
175 | }; | |
176 | ||
177 | static int pcf2127_probe(struct i2c_client *client, | |
178 | const struct i2c_device_id *id) | |
179 | { | |
180 | struct pcf2127 *pcf2127; | |
181 | ||
182 | dev_dbg(&client->dev, "%s\n", __func__); | |
183 | ||
184 | if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) | |
185 | return -ENODEV; | |
186 | ||
187 | pcf2127 = devm_kzalloc(&client->dev, sizeof(struct pcf2127), | |
188 | GFP_KERNEL); | |
189 | if (!pcf2127) | |
190 | return -ENOMEM; | |
191 | ||
192 | dev_info(&client->dev, "chip found, driver version " DRV_VERSION "\n"); | |
193 | ||
194 | i2c_set_clientdata(client, pcf2127); | |
195 | ||
196 | pcf2127->rtc = devm_rtc_device_register(&client->dev, | |
197 | pcf2127_driver.driver.name, | |
198 | &pcf2127_rtc_ops, THIS_MODULE); | |
199 | ||
7ab26cd1 | 200 | return PTR_ERR_OR_ZERO(pcf2127->rtc); |
18cb6368 RC |
201 | } |
202 | ||
18cb6368 RC |
203 | static const struct i2c_device_id pcf2127_id[] = { |
204 | { "pcf2127", 0 }, | |
205 | { } | |
206 | }; | |
207 | MODULE_DEVICE_TABLE(i2c, pcf2127_id); | |
208 | ||
209 | #ifdef CONFIG_OF | |
210 | static const struct of_device_id pcf2127_of_match[] = { | |
211 | { .compatible = "nxp,pcf2127" }, | |
212 | {} | |
213 | }; | |
214 | MODULE_DEVICE_TABLE(of, pcf2127_of_match); | |
215 | #endif | |
216 | ||
217 | static struct i2c_driver pcf2127_driver = { | |
218 | .driver = { | |
219 | .name = "rtc-pcf2127", | |
220 | .owner = THIS_MODULE, | |
221 | .of_match_table = of_match_ptr(pcf2127_of_match), | |
222 | }, | |
223 | .probe = pcf2127_probe, | |
18cb6368 RC |
224 | .id_table = pcf2127_id, |
225 | }; | |
226 | ||
227 | module_i2c_driver(pcf2127_driver); | |
228 | ||
229 | MODULE_AUTHOR("Renaud Cerrato <r.cerrato@til-technologies.fr>"); | |
230 | MODULE_DESCRIPTION("NXP PCF2127 RTC driver"); | |
231 | MODULE_LICENSE("GPL"); | |
232 | MODULE_VERSION(DRV_VERSION); |